Confidence among U.S. home-builders climbed in December for the eighth straight month, reaching its highest level in more than six years and adding to signs the real-estate market is aiding the economic expansion.

The National Association of Home Builders/Wells Fargo index of builder confidence increased to 47, the highest since April 2006, from a revised 45, the Washington-based group reported Tuesday. The December figure matched the median forecast in a Bloomberg survey of 49 economists.